My is lacrosse such a mess when it comes to leagues and or rules on kids and what age/bracket they should play in.
It is real simple they should be playing in birth years period.
I am fine with older aged kids play against younger kids by one year so you so you could even do it in 2 year but do something and stick with it. USA Hockey does it two different ways. Play AAA and ypu play birth year. Play tier 2 use 2 years groupings. There are far less kids playing that sport and they seem to get it right. US Lacrosse should be ashamed of how the run their sports.